An electromagnetic range using a work coil (induction heating coil) which generates an induced current (eddy current) in an object to be heated, such as a pan made of a metal, is known as an electromagnetic induction heating device. This electromagnetic range is configured so as to supply a high-frequency current of 20 kHz or higher to one spiral work coil located under the top plate, thereby generating a magnetic flux may occur in the work coil. As the object to be heated placed on the top plate is magnetically coupled to the magnetic flux in the work coil, an induced current flows into the object to be heated, which is heated with the Joule heat produced by the induced current.
In the electromagnetic range using a single work coil, the magnetic flux generated in the work coil becomes maximum near the center in the radial direction of the work coil. Therefore, the temperature of the object to be heated at the bottom thereof becomes high near the center in the radial direction of the work coil, and becomes low at the other locations to have a heating distribution of a doughnut shape, causing uneven heating.
In this respect, there has been proposed an electromagnetic range that is configured to have a work coil divided into a plurality of heating coils, which are arranged concentrically on the same plane, and are driven by respective high-frequency power generation circuits, thus making the heating distribution of the object to be heated uniform to achieve uniform heating (for example, refer to Patent Literature 1).
Patent Literature 1: Japanese Unexamined Patent Publication No. 2007-257977